The Williams Multigame is an affordable arcade upgrade kit that will add several new features to your original Williams Robotron 2084 or Joust machine. This kit was created and is sold by Clay Cowgill at www.multigame.com.
What the Williams Multigame does is upgrades your Williams game to be a multi-game that plays Robotron 2084, Joust, Bubbles, Defender, Stargate, and Splat!, and it eliminates the lengthy boot time that these games have. It also adds a higly detailed setup menu that allows you to change many game options, and even "black out" certain games from being played.
The reason this kit is possible is because all six of those titles ran on almost identical hardware. So all that was needed for a multi-game was a way for that hardware to access the software for all six titles.
The Williams Multigame kit works by replacing the "Widget I/O Controller" on your original hardware, and adding an expansion card to the sound board, along with a CPU expansion card. This is all pretty much straight forward stuff. The only part that requires thinking is the two power wires that the CPU expansion board requires. Those wires can either be soldered to one of several places on the Williams mainboard, or the can be wired directly to the power supply. This kit also requires an EPROM burner, or someone willing to create the two custom rom chips for you, the kit comes with a blank 27C040 EPROM and a blank 27C256 EPROM, and a DOS application that can create the proper files from a set of ROM images (the MAME ones work just fine). If you do not have an EPROM burner, just post a request to the rec.games.video.arcade.collecting newsgroup and someone there will be able to make them for you. The reason that this kit does not come with the proper EPROMs is because Williams actively defends their older arcade software, while other companies such as Atari do not (or whoever it is that owns Atari this week).
Williams Multigame kits are currently available for $139 at www.multigame.com, and an extra $10 will get you a special "Williams to JAMMA" adaptor, in case you are installing in a JAMMA wired cabinet.
This kit is really a great deal due to the high cost of most classic Williams titles. Although you do have to fabricate a new control panel that can deal with all of these games. But don't worry too much about that, because a few people in the newsgroups are selling new metal panels with all the correct cutouts, and special "Multi-Williams" overlays are supposed to be available soon. Or you can just make you own panel, it really isn't that difficult.
Other similar multi-game kits include the Multi Pac, Tempest Multigame, Multipede and Double Donkey Kong.